A rosszindulatú daganatokban gyakran ún. hypoxiás, csökkent oxigéntartalmú területek vannak (az oxigéntenzió < 7 Hgmm). A preklinikai, valamint klinikai vizsgálatok igazolták, hogy a hypoxia fokozza a tumorok progresszióját, agresszivitását. Szövettenyészeteken tanulmányozva az oxigén hatását, bebizonyosodott, hogy az oxigenizáció in vitro önmagában is gátolja az ép szövetek, a benignus és malignus tumorok sejtjeinek növekedését. Az onkoterápia szempontjából rendkívül fontos megállapítás, hogy ha egy daganatban az oxigén parciális nyomása kevesebb, mint 2,5 Hgmm, a sugárérzékenység lecsökken (intrinszik radiorezisztencia). Hypoxiás tumorokban számos kemoterápiás gyógyszer is hatástalan (kemorezisztencia). Oxigén hiányában vagy hypoxiás szövetekben a fotodinámiás kezelés is eredménytelennek bizonyult. Mindezen kísérleti és klinikai tapasztalatok alapján már évtizedek óta egyes intézetekben kiegészítő kezelésként, de egymagában is próbálkoznak a daganatos betegek oxigenizációjával. A leggyakoribb kezelési forma az oxigéngáz belélegeztetése (hiperbarikus oxigénterápia), vagy az oxigénnel telített víz alkalmazása fürdő vagy ivókúra formájában. A ma már nemzetközi kooperációban is végzett vizsgálatok egyértelműen igazolják az oxigénbevitel jótékony terápiás, radio- és kemoszenzitizáló hatását. Az általánosan alkalmazott eritropoietin-kezelés is bizonyítja az oxigenizáció jelentőségét a tumorterápiában. Időszerűnek látszik Magyarországon szakintézetekben nagy beteganyagon kivizsgálni az oxigenizáció tumorgátló, radio- és kemoszenzitizáló hatását.
Authors:N. Agha, A. Al-hilli, N. Dahir and A. Al-nahhas
A new formulation of stannous-dextran (Sn-Dx) freeze dried kit, containing 60 mg dextran (Dx-70) and 0.08 mg SnCl2·2H2O, to be labelled with99mTc, has been developed. At pH 6.5–7.0. the labelling efficiency was greater than 95%. Gel chromatography column scanning technique was applied for radiochemical purity determination of99mTc-Dx preparation and the degree of in vivo plasma protein binding. Not less than 70% of the administered activity was bound to plasma and remained constant over a 1h period. The biological behaviour after intravenous injection of99mTc-Dx kit was characterized by high and efficient yield of the radiopharmaceutical. The preliminarly clinical results on normal subjects showed that the radiopharmaceutical could be a useful agent for scintigraphy of leg lymph vesel, pelvic and inguinal lymph nodes. The activity uptake in liver and kidney (60 min) was relatively very low, whereas the urinal bladder activity (30 min) represents the drainage of the activity entering the blood stream after interdigital injection of99mTc-Dx.
Authors:C. Acar, S. Teksoz, P. Ünak, F. Biber Müftüler and E. Medine
The aim of this study is to investigate stereoisomeric behavior of penicillamine and the effect of temperature on labeling.
In addition, it was explored how stereoisomerism affected biological behavior of them. In the present work, D- and L-enantiomers
of penicillamine(D-PA, L-PA) were labeled with 99mTc using SnCl2 as reducing agent and their radiopharmaceutical potentials were investigated. Quality control procedures were carried out
using thin layer radiochromatography (TLRC), electrophoresis and high performance liquid radiochromatography (HPLRC). HPRLC
chromatograms showed two peaks for 99mTc-D-PA, while a single peak was observed for 99mTc-L-PA at room temperature. However, the single peak was observed at 90 °C for both isomers. Labeling yields of each isomer
were found to be over 98%. Biological activity of these complexes was determined on male Albino Wistar rats by biodistribution
studies. While the biodistribution result of 99mTc-D-PA showed high uptake in the liver, maximum uptake of 99mTc-L-PA was observed in the kidneys. Both two complexes were cleared rapidly from the blood, mainly by the renal system. Since
the activity concentration of 99mTc-D-PA at the 30th minute in the kidneys and the liver reached a maximum value and at the 120th minute, it was removed by
renal and hepatobiliary excretion. As a result, it can be concluded that stereoisomerism affect not only the chemical behavior,
but also differs their biological behavior of these compounds.
Authors:Hu Song, Shunzhong Luo, Hongyuan Wei, Hongtao Song, Yuqing Yang and Weiwei Zhao
The mass production and extensive applications of nanomaterials may have potential negative effects on health of human beings.
Research on the in vivo behavior of fullerene, the most representative nanomaterial, just begins. In order to investigate
the in vivo behavior of fullerene derivative and to explore new biomedical application of fullerene, fullerol, C60(OH)20, was labeled by 99mTc(CO)3. The labeling conditions were optimized. Gamma counter and SPECT were used to access the in vivo biological behavior of the
complex. Results showed that the complex was stable in mice body. The complex was delivered to all tissues rapidly except
for brain. A significant percentage of total activity was retained in 3 h, particularly in the liver, spleen, lung, thyroid,
kidney and bladder, which indicated the mononuclear phagocyte system (MPS) took an important part in clearing the complex
and the complex was mainly excreted through urine. The low radioactivity of all tissues and organs in 24 h indicated that
the cleanup speed was rapid. The high uptake and rapid cleanup speed of the complex in important organs hinted fullerene could
be used as carrier for in vivo radionuclide decorporation agents.
The preparation and biological behaviour of99mTcN-tropolone is described. This complex was found to be more lipophilic than the99mTc-tropolone complexes obtained using stannous chloride as a reducing agent and when injected i.v. into mice was found to label blood cells. The agent may have potential as a blood cell labelling agent.
Authors:E. Havránek, A. Bumbálová, M. Beláková, M. Komová and P. Křenek
In this paper, the labeling characteristics and biological behavior of five aminopolycarboxylic acid derivatives have been studied: N-(phosphonomethyl) nitrilodiacetic acid (99mTc-MPIDA), N,N-(diphosphono) aminoacetic acid (99mTc-GDP), N-(2-carbamoylethyl) nitrilodiacetic acid (99mTc-KEIDA), N-(2,3-dihydroxypropyl) nitrilodiacetic acid (99mTc-DPKA), 2-[N-(2-hydroxyethyl)-N-carboxymethyl] aminopropanoic acid (99mTc-EAPA).
The aim of this study is to examine biological behaviour of radiolabeled guanine with [Tc(CO)3]+ core in vitro and in vivo. In vitro biological behavior of 99mTc(CO)3–Gua was evaluated on Lung (A-549), Breast (MCF-7), Colonic (Caco) carcinoma cell lines and normal human bronchial epithelial
(NHBE). 99mTc(CO)3–Gua compound showed high uptake on A-549 cell line when compared to NHBE cell line. Biodistribution characteristics of 99mTc(CO)3–Gua was evaluated using New Zeland Rabbits. Scintigraphic results showed that a high level of radioactivity was observed
in the lungs and liver shortly after administration of the 99mTc(CO)3–Gua and excretion takes place via both renal and hepatobiliary route. It was concluded that 99mTc(CO)3–Gua could be used as a nucleotide radiopharmaceutical for imaging purposes.
The purpose of this work was to label polyclonal antibodies with99mTc such as photoactivated IgG and to check the radiochemical and biological behavior of the labeled product. Experiments were
carried out to found the formulation of optimal binding of99mTc to polyclonal IgG. In addition animal studies in normal mice and in mice bearing a promoted inflammation foci were performed.
The labeled product was analyzed by size-exclusion HPLC and ITLC. Higher amount than 23μg of tin per 500μg of protein gave
between 87% and 93% labeling. Protein concentrations between 1.5 and 5 mg/ml gave 90% labeling yields.
The synthesis of a complex molecule with its coordination center composed by a triamide monomercaptide tetradentate set of donor groups plus a phenyl-acetyl group as protector group of a sulphur atom is reported. This compound has been mixed with immune glubulin G, labeled with 99mTc and purified by high resolution liquid chromathography (HRLC). The biological behavior of this labeled compound was evaluated with mice of Balb-C origin, showing the biological properties of a protein. This molecule might be another option for radio-immuno-scintigraphic analysis when using proteins of antigenic nature.
Authors:S. Pervez, A. Mushtaq, M. Arif and Z. Chohan
The preparation of 188Re-glucoheptonate (GH) is described using 188Re, which was obtained from an alumina based 188W/188Re generator. The dependence of the radiolabeling yields of 188Re-GH on reducing agent concentration, GH concentration, pH, temperature and incubation time was examined. In the case of optimum conditions the yield of 188Re-GH was ~99%. The ITLC technique was employed to monitor the different species formed. A biodistribution study of 188Re-GH was carried out in rats and compared to the biological behavior of 99mTc-GH.